Software
Houzz Logo Print
the_writ

Soil Test Results

17 years ago

Greetings all! I just recently discovered your forums and am extremely impressed by the community here and look forward to becoming a part of it. If I may, I have couple questions and am in need of some advice.

I just got my soil sample results back from the LSU Ag Center and am not quite sure where to proceed from here. I am starting a vegetable garden in my back yard and would like to make sure the soil is "up to snuff" so to speak. The area is approx 1200 square feet (24 feet wide and 50 feet long)along my backyard fence. The issue I have is that for 30+ years we had banana trees growing very thickly along the fence line out about four feet into the yard. Every winter we would cut them down and lay them to rot along the stumps and they would grow back in the spring. Well now the banana trees are long gone and my garden will stretch into this area. I took soil samples from the area that used to have the banana trees and again from the lawn area and got back two totally different results.

Soil Sample #1 (Banana tree area)

Soil Type: Silt Loam

pH (1:1 Water) 6.58 High

Phosphorus, ppm 133.64 Very High

Potassium, ppm 206.93 Very High

Calcium, ppm 1,488.64 High

Magnesium, ppm 260.68 High

Sodium, ppm 8.40 Optimum

Sulfur, ppm 14.01 Medium

Copper, ppm 1.44 High

Zinc, ppm 18.40 High

Soil Sample #2 (Lawn Area)

Soil Type: Silt Loam

pH (1:1 Water) 5.66 Optimum

Phosphorus, ppm 44.24 Medium

Potassium, ppm 40.55 Low

Calcium, ppm 941.57 Low

Magnesium, ppm 51.17 Very Low

Sodium, ppm 9.44 Optimum

Sulfur, ppm 13.92 Medium

Copper, ppm 1.48 High

Zinc, ppm 6.34 High

As you can see they differ greatly in a few areas. My thoughts would be to till (I'm a Tiller lol) up the area down to 12" and then mix the soils from the two areas together while adding compost, sphagnum peat, and a bit of manure then spread it all back out. I'm hoping this will balance out the highs and to lows to some degree. If anyone has any suggestions on how to remedy this situation such as additives and such please feel free to pass them on. I would really be grateful. Thank a bunch.

Michael

Comments (9)

  • 17 years ago

    What are you planning on growing there? I am not sure why that lab would think a soil pH of 6.58 would be high since that is in the optimal range for most plants, except those that like an acidic soil. Then sample 2 has a soil pH of 5.66 and is listed as optimum and I have not seen anything, anywhere that lists that, for a lawn, as desireable. Everything I have seen on lawns and soil pH would be in the range of 6.2 to 6.8.
    I would dig in and look at what the level of organic matter was in those soils as well as how those soils drain, hold together (tilth), smell, and what kind of life is in them and these simple soil tests can help you determine that,
    1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

    2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

    3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

    4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer you soil will smell.

    5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

  • 17 years ago

    Thanks for the reply kimmsr. I'm making a vege garden with Tomatoes, Peppers, Beans, Broccoli, Cauliflower, Carrots, Onions, and Potatoes. Might try a couple watermelons as well. I too was wondering about the pH reading.

    About a week ago when I gathered the soil samples I did the experiments that you had suggested. My results were as follows.

    1) Structure: Did the jar test and what I got was 3/4 inch of sand on the bottom and the rest was silt. I didn't see another layer on top for organic. I used six inches of soil instead of four. Will that matter? If so I will redo.

    2) Drainage: Took a little over three hours to drain fully.

    3) Tilth: The clump held together as you described and then fell apart rather easily when I poked it.

    4) Smell: Smell was a nice and rich earthy odor. No unpleasant smell that I noticed.

    5) Life: None of the shovels of dirt had any worms in it. One of the shovels of dirt by the fence line where some tall weds were growing did have a few very teeny tiny snails on the top layer. Guess there will be some beer traps in my future lol.

    Michael

  • 17 years ago

    The 4 inch soil level is what makes the math easy and is why it is used. Some universities that have that same test say use 3 inches of soil, but the 4 inches will not require some kind of adjustment for quantity that the others will.
    That you saw very little organic matter and saw little soil life go hand in hand. Earthworms are an indication of what else is in your soil and they need organic matter to live on as do the other, more microscopic, thingies that make for a good, healthy soil. Those that live in Louisiana do have a disadvantage because your soil temperatures seldom drop low enough to slow, much less stop, soil bacterial activity so they are at work digesting the OM in your soil year around and therefore you need about twice as much OM as I do, maybe even more.

  • 17 years ago

    Ahh that makes sense about the OM - Worms - Soil Temp. I guess the addition of lots of compost will be helpful to build back up the OM. Do you think mixing the soil from the two areas will help balance out the elements such as Calc , Potass and Mag or will I need to add anything extra besides the compost, peat and manure? I am worried about adding amendments and over doing it to the detriment of my pH level and therefore my plants. Thank you very much for your help!

  • 17 years ago

    Kimmsr: I can think of an example of too many worms being a bad thing. I once had a garden in Colorado that had so many worms that when they came up after a rain their density was so high they'd burrow right through my seed lines, appx. 1 worm hole/2 sq in. the holes were about pencil sized and larger. I often had to reseed rows due to the damage, never seen anything like it before or since.

    Michael

  • 17 years ago

    Since compost is organic matter adding compost to soil can be a good thing. Mixing the soil from each area may balance out the nutrient levels but that would take quite some time to accomplish, as well as a lot of work, just add compost to each area as well as other forms of organic matter. Often people that add just compost to their soil will not see an increase in the humus level, the amount of residual OM left in the soil.

  • 17 years ago

    Yeah mixing the two areas via shovel and hoe will be quite a chore but will be some good exercise lol. I plan on adding a good amount of compost, sphagnum peat, and some manure then mix it in really well. After all is said and done I will probably take more soil samples to the extension office and see how the levels are after the mixing. Hopefully I can achieve some sort of a balance by doing this. The problem is it's time to start planting and I am itching to get started. I am shooting for this weekend to get started and hopefully get the plants in the ground by the beginning of next week. Thanks again for your help. I really appreciate it. If you or anyone else has any more advice I would love to read it.

    Michael

  • 17 years ago

    Wait for another soil test until next year, or later in the fall. It takes time for any change you make to make any change (if that does make sense) so mixing in a bunch of stuff and then sending in a soi lsample will not show much, if any change.

  • 17 years ago

    Ahh then I will wait on the second set of soil tests. No reason to spend the money if I don't have to. Thanks again for your advice. It's much appreciated.

    Michael